(x+6)^2 is less than or equal to 8...i have to solve the inequality....

To learn how to solve quadratic inequalities (the first step of yours is to multiply out the left-hand side and move the "8" over), try here.

im having trouble factoring x^2+12x+28 I tried factoring the problem out and using the quadratic formula and neither worked.

The Quadratic Formula is for solving, not factoring, so that wouldn't apply. For factoring, you have to find factors of +28 (so they'll both have the same sign) that add to +12 (so they'll both be positive). What are the possible factor pairs? Do any of these pairs work?